/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.transforms.join;



import com.bff.gaia.unified.sdk.values.TupleTag;

import com.bff.gaia.unified.sdk.values.TupleTagList;



import java.io.Serializable;

import java.util.HashMap;

import java.util.List;



/**

 * A schema for the results of a {@link CoGroupByKey}. This maintains the full set of {@link

 * TupleTag}s for the results of a {@link CoGroupByKey} and facilitates mapping between {@link

 * TupleTag}s and {@link RawUnionValue} tags (which are used as secondary keys in the {@link

 * CoGroupByKey}).

 */

public class CoGbkResultSchema implements Serializable {



  private final TupleTagList tupleTagList;



  public static CoGbkResultSchema of(List<TupleTag<?>> tags) {

    TupleTagList tupleTags = TupleTagList.empty();

    for (TupleTag<?> tag : tags) {

      tupleTags = tupleTags.and(tag);

    }

    return new CoGbkResultSchema(tupleTags);

  }



  /** Maps TupleTags to union tags. This avoids needing to encode the tags themselves. */

  private final HashMap<TupleTag<?>, Integer> tagMap = new HashMap<>();



  /** Builds a schema from a tuple of {@code TupleTag<?>}s. */

  public CoGbkResultSchema(TupleTagList tupleTagList) {

    this.tupleTagList = tupleTagList;

    int index = -1;

    for (TupleTag<?> tag : tupleTagList.getAll()) {

      index++;

      tagMap.put(tag, index);

    }

  }



  /**

   * Returns the index for the given tuple tag, if the tag is present in this schema, -1 if it

   * isn't.

   */

  public int getIndex(TupleTag<?> tag) {

    Integer index = tagMap.get(tag);

    return index == null ? -1 : index;

  }



  /** Returns the tuple tag at the given index. */

  public TupleTag<?> getTag(int index) {

    return tupleTagList.get(index);

  }



  /** Returns the number of columns for this schema. */

  public int size() {

    return tupleTagList.getAll().size();

  }



  /** Returns the TupleTagList tuple associated with this schema. */

  public TupleTagList getTupleTagList() {

    return tupleTagList;

  }



  @Override

  public boolean equals(Object obj) {

    if (obj == this) {

      return true;

    }

    if (!(obj instanceof CoGbkResultSchema)) {

      return false;

    }

    CoGbkResultSchema other = (CoGbkResultSchema) obj;

    return tupleTagList.getAll().equals(other.tupleTagList.getAll());

  }



  @Override

  public int hashCode() {

    return tupleTagList.getAll().hashCode();

  }



  @Override

  public String toString() {

    return "CoGbkResultSchema: " + tupleTagList.getAll();

  }

}